Lower alkylpolysiloxaneborates and their production



minutiae, a

4 35 f1 7 LOWER aLKY roLY-snoxAurnom'ms v THEIR PRopUQTIoN WintonII.'Patnode. Schenectady, N. 12,. assignmto General Electric co New York rNo Drawing.

mp any, a corporation of Original application July 1, 1944, 1

Serial No. 543,209. Divided and this applica- 7 tion November 30, 1945,Se'rialfltlo, 632.132

This application is'a division 7 application'Serial No. 543,209, filedJuly 1, 1944,

of. my copending 5 Claims. (c1. zed-fem."

and assigned to the same assignee as the present invention.

The invention disclosed and claimed in the" above-identified parentapplication Serial No.

543.209 broadly relates to the treatment ofrsolid' bodiesto render thesurfaces thereof water-repellent, and is especially concerned with awaterrepellent treatment for ceramic and other vitreous bodies, e. g.,glass.

Methods of producing water-repellent materials by treatingwater-non-repellent bodies, in-- cluding ceramic bodies, withorgano-silicon halides (organohalogenosilanes) in vapor form aredescribed in. for example, my Patent No. 2,306,- 222, issued December22,1942, and assigned-to the same assignee as'the present invention.

borate' derivatives, and more specifically with compositions comprisingthe Si-containing (i. e., silicon-containing) material or complexobtamed by effecting reaction between boric acid and loweralkylhalogenopolysiloxane substance containing an average of from about0.16 to 1.0

' halogen atom per silicon atom.

Glass and other vitreous and ceramic mate- ".rials that have beentreated in accordance'with the invention disclosed and claimed in theaboveidentified parent application have been found to have waterrepellent surfaces which are superior to those obtained by the use oforgano-silcon halides both in durability and efiectiveness. Thecompounds employed in practicing that invention are easier to handle andapply than are the or- Brie fiy described, the invention disclosed andclaimed in my above-identified parent application is based on thediscovery, that the surfaces of solid bodies, particularly the surfacesof ceramic articles, can 'be conveniently rendered water-repellent bytreatment with lower alkyl polyjsiloxanes containinghalgen atoms orother reactive substituents (more specifically radicals or groups)connected to some of the silicon atoms.

Examples of polys'iloxanes whichcan be employed in practicing theinvention claimed in parent application Seria-l No. 543,209arethe'symmetrical j methyl dichlorosiloxanes and otherlower-alkylhalogenosiloxanes described in my application Seneighborhoodof, surfaces attacked by hydrogen halides. v b

Although the invention claimed inmy parent copending application SerialNo. 543,209 is applicableto the treatment of a number of inorganicmaterials, it is particularly adapted to the treatment of glass productswhere optical clarity rial No. 463,812, filed October 29, 1942, now Patsigned to-the same assignee as .the present invention, more particularly:organo-silicon com- 7 ent No, 2,381,366, issued August '1, 1945, andasr pounds havingthe formula X(SiR20)nSi-R2X wherein X represents ahalogen atom, R represents a monovalent lower alkyl group, and n is awhole number and is equal to at least 1, e. g.,

tetrame'thyl-l.2-dichlorodisiloxane, hexamethyl- Ls-dichlorotrisiloxane,octamethyl-lA-dichloro-i tetrasiloxane, etc.

such as aircraft, etc.

Examples of other polysiloxanes that canbe employed in carrying into,efiect the invention clalmed'in the aforementioned parent applicationare thecorresponding esters, borates and amines of. the siloxanederivatives claimed in my aforementioned Patent No. 2,381,366, whichcompounds may beprepared by, for example, reacting these boric acid orammonia. The invention claimed in the present divisional applicationisconcerned particularly with compositions comprising the of thetreatedglass is of prime importance. Since the treatment. can be appliedwithout the use of any special apparatus, it is ideally suited as ananti-rain treatment for Windshields and windows in automobiles, ships,swiftly moving vehicles A small quantity of the treatingrcompound or asolution thereof in an inert solvent such as toluene, gasoline, ethers,etc., is applied, to the surface of the glass and the excess material isrubbedofi with a clean cloth. Thereis no visible film on the treatedsurface; windowsand windshieldsso treated permit better visibility in arainstorm than do the untreated windows and Windshields. Under someicing orfrosting conditions the "treatment definitely retards loss ofvisibility due to. the forand other halogenosiloxanes to be describedmore fully hereinafter with suitable aliphatic alcohols,

mation of iceor frost, andjany iceor frost which does collect is moreeasily removed from treated surfaces, by wiping or by heat, thanfromuntreated surfaces.

There is apparently a chemical reaction between the treating materialand the vitreous surface, since the treated surfaces'can be washed withsoap and water. or with alcohol. acetone, benzene. etc., or rubbed witha cloth without los ing their water-repellent or anti-rain properties.

This treatment not only increases the contact 7 angle between water andglass. but also increases the ease with which the dropsslide off theglass. The treating compounds in themselves function as cleaning iluidsfor the glass surfaces. If desired. various inert cleaning solvents ormild abrasives such .as ta1c.- chalk or infusorlal earth may be addedtothecompounds to improve this cleaning action. Household glassware anddishes benefit from treatment with theherein described treatingcompounds in that they are more easily kept clean and are much easier todry after wash ing. The treatment also retard the formation of theopaque fllm which sometimes appears on glass, thus maintaining theoriginal appearance.

The substituted lower alwlf polysiloxanes found to be suitable forpracticing the invention claimed inmy above-identified parent copendiuggen halide, or should be applied as mixtures with thehalogenopolysiloxanes to increase the chemical reactivity of the esters.

The borates with which the present invention is concerned. moreparticularly borates of loweraikylhalogenopolysiloxane substance thatcontains an average of from about 0.16 to 1.0 halogen atom persiiiconatom, canbe preparedby treat ing'the correspondinghalogenopolysiloxane substance with-boric' acid. For example, 12.4 gramsof boric acid w'as'partially'dissoived andpartiallysuspendedinaooccof-glacialaceticadd. and to the mixture wasaddeddropwiseovet a periodof minutes 105.4 grams of ahalogenopolysiloxane represented by, the formula cmcnms omcmnsici and which maybe named octamethyl-i, 4-mchlorotetrasiloxanc.- sun-mg. continuedapplication include the pure or mixed methyl,

ethyl and propyl polysiloxanes containing at least one, preferablyapproximately two, hy-

drolyzable'atoms or groups connected to,

atoms. The hydrolyzable substituentsmay be throughoutaddition "andifor1% hours-ditchwards. The reaction separated into two phases afterstirring was stopped. The upper phas'e'cdntainlng thereaction productwassephalogenaparticularly chlorineor'bromine atoms. or lower alkoxyradicals, amino radicals or bo'rate,

radicals. For maximum water-repellency and ease of application, I preferto'employ the polyalkyl-chloropolysiloxanes, p a r t i c ul a rl y thestraight-chain, halogenated polysiloxanes or mixtures of suchpolysiloxanes having the gen eral formula x(SiR:O) sSiRiX. wherexrepresents a halogen atom, specifically a chlorine j atom, Itrepresents a monovalent lower alkyl group, particularly a methyl group,and n i an integer equal to at least 1, preferably from 3 to about 7.Such polysiloxanes contain an average of from about 0.25 to 1,preferably 0.3- to 0.5.

halogen atom per silicon atom. In other words,

an average of from about 0.25 to 1, preferably 0.3

to 0.5, of the silicon atoms are each connected to a halogen atom. Othersuitable halogeno-polysiloxanes include the halogenated branchedchainpolysiloxanes and halogenated polysiloxanes containing terminalRaSl-groups. Such compounds can be prepared, for example, by partialhydrolysis of dialkyldihalogenosllanes such as dimethyldichlorosilanecontaining up to approximately 10 per cent,;by weight, of a'trialkylhalogenosilane, such as trimethylchloro- I silane, or analkyltrihalogenosilane such as methyltrichlorosilane, or both, to thepoint where g the principal products are lower alkyl poly siloxanescontaining one or more halogen atomsper molecule. Halogenopolysiloxanesor mixtures thereof especially suitable for use in practicing theinvention claimed in parent application Serial No. 543,209 contain from2 to 8 silicon atoms, have an average R/Si ratio of from about 1.8 to2.5 and an average Hal/Si (halogen/silicon) ratio of from 0.16 to 1,preferably 0.3 to 0.5, the remaining valences of the silicon atomsbeins-taken up by oxygen.

When the treatment is to be applied to, or in the neighborhood of,unprotected metal surfaces which are readily corroded byhydrogen'halides, it may be found desirable to employ polysiioxanesofthe above type in which all or part (i. e., at

least some) of the halogens attached to silicon have been replaced bythe less corrosive amino, lower .alkoxy or borate (oxyboron) radicals.The esters usually should contain some halogen attached to silicon or asmall quantity of a hydroperfectly arated the acetlcgacidand a portionthereof was applied' 'to-a A very faint opaquenesszwas noticed-afterexcess had been off. was water-, repellent, and jwhen washedwithalcohol' became probably due to precipitated boric .acid formed onhydrolysis or byreactionwith tbeglas's-surface, which acid w s dissolvedo1, washed away lthealcohol. v

The treating agents hereinbefore described are applicablenotonlytothe-treatment of glass 'surfaces to render such surfaceswater-repellent. but

also to all types of ceramic articles and surfaces 1 of i a siliceouscharacter, including glazed or enamelled articles, porcelain,quartz,.glass fiber, etc,. Metalssuch as stainless steel, nickeLPhosphorbronze and aluminum are examples of other organic'ma'ter'ials; thesurfaces of which can be renderedwaterrepellent' by treatment with thepoiysiloxane-derivatives described herein.

rom t e fore o ng d s n i l e s en that 'thej present invention providesnew. and

,usefulfcompos'itions. of" matter comprising a borateoflower (e'. a;methyl) halogenopolysiloxane. substance containing an average I of fromabout 0.16 to 1.0;halogen atom per-sill con atom; more particularlyaborateof lower alkyl (e. g., methyl) 'chloropol'ysiloxane substancecontaining an average of from about 0.16 to 1.0

chlorine'Iatom per silicon atom, including l quid compositionscomprising a solution of a "borate of the kind just described. Suchborates, all of which are Si-containing materials, are obtained by, forexample-effecting between borlo acid and iower alkylhalogenopolysiloxanesubstancecontaining anaverage offromabout 0.16 to 1.0 halogen-atom persilicon atom. Also within' the of the present invention are productscomprising'the Si-containing composition without. losin its water vrepellent qualities; ;.The.original 01 80118 8 5. was

atom. a'speciflc example of the substance of (2) beingoctamethyl-L4-dichlorotetrasiloxane.

The scope of the invention also includes method features, moreparticularly the method or preparing a new Si-containing material whichcomprises eifecting reaction between boric acid and alower-alkylhalogenopolysiloxane substance containing an average of fromabout 0.16 to 1.0 halogen atom, specifically a chlorine atom, P rsilicon atom; as well as the method of preparing a new Si-containingmaterial which is especially suitable ior use in the treatment or solidbodies to render the surfaces thereof water-repellent, said methodcomprising effecting reaction between boric acid andoctamethyl-1,4-dichlorotetrasiloxane, and isolating the resultingSi-c'ontaining material from the reaction mass.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A composition comprising a borate of loweralkylpolysiloxane.

2. A liquid composition comprising a solution oi a borate oflower-alkylpolysiloxane substance containing an average of from about0.16 to 1.0 borate radical per silicon atom.

4. As a new composition oi matter, a borate of methylpolysiloxanesubstance containing an average 0! from about 0.16 to 1.0 borate radicalper silicon atom.

5. The method oipreparing a new Si-containing material which comprisesmixing boric acid and lower-alkylhalogenopolysiloxane substancecontaining an avera e of from about 0.16 to 1.0 halogen atom per siliconatom.

'WIN'I'ON I. PATNODE.

REFERENCES CITED The followingv references are of record in the flle ofthis patent:

UNITED STATES PATENTS Number Name Date 2,190,746 Von Glahn Feb. 20. 194025 2,371,068 Rachow Mar. 6, 1945

